Crop protection netting

ABSTRACT

Crop protection netting for covering trees or other plants for insect or bird exclusion is of a knitted mesh construction, including knit intersections in the netting and connecting yarn portions between the yarn intersections which extend substantially linearly between intersections. The netting is lightweight and stretchable in multiple directions.

This is a national stage application in the United States ofInternational Application No. PCT/NZ2011/000180 filed 2 Sep. 2011, whichclaims priority to New Zealand application no. 587761 filed 2 Sep. 2010,the entire disclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to crop protection netting for use overgrowing plants, vines, bushes, or trees (herein: plants) in agriculturalapplications.

BACKGROUND TO THE INVENTION

Crop protection netting may be used to cover crops while they aregrowing. One type of crop protection netting comprises a line knitconstruction with joining filaments as shown in FIG. 8. Another type ofcrop protection and comprises knitted netting defining diamond shapedapertures as shown in FIG. 9 with the netting yarn on all sides of thenetting mesh apertures being continuously knitted or knotted.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved or atleast alternative crop protection netting.

In a first aspect the invention broadly comprises crop protectionnetting having a greater length than width and which is of a knittedmesh construction, knitted such that at yarn intersections in thenetting multiple yarns of which the netting is formed are knitted aroundeach other to define the netting mesh apertures so that the netting isstretchable in multiple directions, and wherein connecting yarn portionsbetween said yarn intersections extend substantially linearly betweenintersections.

Preferably the netting is knitted from multiple yarns all extendingalong a length of the netting. In a preferred form each yarn follows anapproximate zig-zag path path along the length of the netting, loopingat each intersection in the netting comprising the yarn, to a furthernetting yarn intersection one on one side and one on another side.

In another aspect the invention broadly comprises crop protectionnetting having a greater length than width and which is of a knittedmesh construction, knitted from multiple yarns extending along a lengthof the netting and following an approximate zig-zag path path along thelength of the netting, looping at each intersection in the nettingcomprising the yarn, to two further netting yarn intersections one onone side and one on another side.

In a preferred netting construction of the invention as will be furtherdescribed with reference to the accompanying figures, each intersectionis formed by knitting together of three yarn parts passing through theintersection:

-   -   a first yarn which enters the intersection along a first axis        and exits the intersection along the same first axis, so that a        first connecting portion to a first adjacent intersection        comprises adjacent lengths of the same yarn,    -   a second yarn which enters the intersection along a second axis,        passes through the loop within the intersection of the first        yarn, and extends to and returns from a second adjacent        intersection along a third axis so that a second connecting        portion to that adjacent intersection comprises adjacent lengths        of the same yarn, and exits the intersection along a fourth        axis, and    -   a third yarn which enters the intersection along the second axis        so that a third connecting portion from a third adjacent        intersection comprises portions of both the second and third        yarns, passes through the loop in the intersection of the first        yarn, and exits the intersection along fourth axis with the        second yarn, so that a fourth connecting portion to a fourth        adjacent intersection comprises portions of both the second and        third yarns.

In another preferred netting constructions of the invention as will befurther described with reference to the accompanying figures, eachintersection is formed by knitting together of three yarn parts passingthrough the intersection:

-   -   a first yarn which enters the intersection along a first axis,        firstly creates an extra loop and exits the intersection along        the same first axis, so that a first connecting portion to a        first adjacent intersection comprises adjacent lengths of the        same yarn,    -   a second yarn which enters the intersection along a second axis,        passes through the loop within the intersection of the first        yarn, and then goes behind the loop created by the first yarn to        create an extra loop and then extends to and returns from a        second adjacent intersection along a third axis so that a second        connecting portion to that adjacent intersection comprises        adjacent lengths of the same yarn, and exits the intersection        along a fourth axis, and    -   a third yarn which enters the intersection along the second axis        so that a third connecting portion from a third adjacent        intersection comprises portions of both the second and third        yarns, passes through the loop in the intersection of the first        yarn, and exits the intersection along fourth axis with the        second yarn, so that a fourth connecting portion to a fourth        adjacent intersection comprises portions of both the second and        third yarns.

And each yarn intersection in the netting is connected to adjacent andsurrounding yarn intersections by connecting yarn portions eachcomprising at least two yarn lengths. Preferably, each yarn intersectionin the netting is connected to adjacent and surrounding yarnintersections by connecting yarn portions each comprising at least twoyarn lengths that are at least free of knots or loops for 2 mm or morein length between the intersections.

Preferably the netting comprises rows of said yarn intersectionsadjacent to one another in a first axis or direction across the netting,typically across a machine or manufacturing axis or direction of thenetting. Preferably in immediately adjacent rows of yarn intersectionsin a second direction substantially orthogonal to said first direction,typically a machine or manufacturing axis or direction of the netting,the yarn intersections of the adjacent rows are staggered relative toone another.

Preferably the width of the netting is substantially uniform along thelength of the netting.

Preferably the mesh size is in the range of approximately 3 mm to 20 mm,0.3 mm to 10 mm, more preferably approximately 3 mm to 8 even morepreferably 4 mm to 6 mm, even more preferably 3 mm to 5 mm, even morepreferably approximately 3.5 mm to 4.5 mm, and most preferablyapproximately 4 mm.

In one form each mesh aperture comprises four yarn sides between knittedyarn intersections. In a preferred form the lengths of the sides aresubstantially equal. The netting may alternatively be knitted so thatthe lengths of the mesh aperture sides are unequal or so that the meshapertures have more than four sides in more complex mesh apertureshapes, for example but not limited to hexagonal shaped mesh apertures.In the four-sided mesh form of the netting the shape of the aperturesmay be substantially square, rectangular, triangular, or any othershape. The mesh aperture shape is referred to when the netting isequally and maximally taut but not stretched in both its length andwidth directions.

In one form the netting is formed from elastic yarn. In another form,the netting is formed from non-elastic yarn. In another form the yarn isformed from yarn that has some elongation when stretched but is neitherelastic or non-elastic.

In a preferred form the netting is reflective. In another form thenetting is non-reflective. In some embodiments the yarn forming thenetting may be any of the following: black, white, transparent ortranslucent, white (UV or non-UV reflecting white) in colour, coloured,formed from a non-pigmented material, formed from plastic, or formedfrom a range of polymers.

In one form the netting is formed by twin, triple, or multiple or singlemonofilament fibre yarns. In one form the yarn is monofilament.Preferably, the monofilament has a substantially circular cross-section.More preferably the yarn has diameter in the range of approximately 0.1mm to 1 mm, even more preferably 0.2 mm to 0.8 mm, and even morepreferably 0.2 mm to 0.4 mm, and more preferably 0.2 to 0.3 mm and mostpreferably 0.15 mm to 0.25 mm In denier, the yarn is preferably in therange of approximately 50 to 1000 denier, more preferably 50 to 700denier, even more preferably 100 to 500 denier, even more preferably 100to 300 denier, even more preferably 150 to 250 denier or even morepreferably 200 to 300 denier

Typically the netting is machine-knitted for example on a warp knittingmachine or a weft insertion warp knitting machine.

Preferably the weight of the netting is in the range of approximately 10to 100 grams per m², more preferably 15 to 80 grams per m², even morepreferably 20 to 60 grams per m², even more preferably 20 to 40 gramsper m², or more preferably 30 to 40 grams per m² and even morepreferably 25 to 35 grams per m^(2.)

In some embodiments the yarn may incorporate a compound or compoundsadded to cause or increase the extent to which the material reflectsand/or absorbs radiation from the earth (terrestrial (long wave orinfrared) radiation). Thus when the netting is placed over plants itwill assist in retaining heat beneath the material, which may bedesirable for some plants or applications.

In some embodiments the yarn may incorporate a compound or compoundsadded to cause or increase the extent to which the netting allowstransmission and/or absorption of radiation from the earth (terrestrial(long wave or infrared) radiation). Thus when the netting is placed overor adjacent to plants it will assist in releasing the heat beneath thenetting, which may be desirable for some plants or applications.

In other embodiments the yarn may incorporate a compound or compoundsadded to cause or increase the extent to which the netting reflectsand/or absorbs solar radiation. Thus when the netting is placed overplants it will assist in cooling beneath the material, which may bedesirable for some plants or applications.

In other embodiments the yarn may incorporate a compound or compoundsadded to cause or increase the extent to which the netting allowstransmission and/or absorption of solar radiation. Thus when thematerial is placed over plants it will assist in increasing the heatbeneath the material, which may be desirable for some plants orapplications.

In a further aspect the invention broadly consists in a method ofprotecting plants comprising the step of at least partially covering aplant or row of plants with a crop protection netting of the firstaspect of the invention.

In one form the step of covering the plant(s) comprises securing thenetting over the entirety of the plant(s) and securing or fixing it tothe ground surface surrounding the plants.

In another form the step of covering the plant(s) comprises suspendingor supporting the netting over the top of the plant(s) as a canopy usinga supporting structure or framework.

The term “yarn” as used in this specification, unless the contextsuggests otherwise is intended to mean multi or mono filament yarn,threads or fibres. The term “yarn” unless the context suggestsotherwise, is intended to include longitudinally extending singlefilament elements having four sides when viewed in cross-section, suchas a rectangular or square cross-section, also longitudinally extendingelements having a multisided cross-section such as a triangular orhexagonal cross-section for example, and also longitudinally extendingelements having a circular or oval or similar cross-section (sometimesreferred to hereafter as monofilament). The yarns may be formed from anysuitable polyolefin such as polyethylene or polypropylene, for example,or a mixture thereof, or an ethylene alpha-olefin, or a polyester, or abiopolymer, or a blend of any of the foregoing. Certain plastics areparticularly useful when present as minor or major components. Ethylenevinyl acetate (EVA), ethylene butyl acrylate (EBA) and ethylene methylacrylate (EMA) are useful for imparting elasticity and other properties.Polyesters and polystyrene, styrene-butdienie (SB),acrylonitrile-butadienie-styrene (ABS), styrene-aciylonitrile (SAN),polyethylenie terephithialate (PET), polymethylmethacrylate (PMMA) andpolycarbonate are useful as dye carriers and also for influencingradiation (reflecting, absorbing and transmission) properties and alsoother properties on the materials. Starch and other plant polymers areuseful to increase biodegradability. Alternatively the yarns maycomprise in part or whole of paper, wood or cellulose fibre, starchbased polymers, casein, latex or in any combination of the above and/orwith petroleum derived plastic polymers. The polymer or polymer blendmay incorporate agents such as one or more pigments, LTV stabilisers, orprocessing aids.

The phrase “mesh size” as used in this specification, unless the contextsuggests otherwise, is defined for the four-sided and equal-length sidesform of mesh apertures as the length of the sides of the mesh aperture,or a substantially equivalent cross-sectional area for non-equi-lengthsided mesh apertures or other more complex mesh aperture shapes formedby more than four sides, the cross-sectional area being determined whenthe netting is taut but not stretched in both directions.

The term “reflective” as used in this specification is intended to meanthat the netting filament or yarn themselves, excluding the air spaces,is reflective of at least 20%, or 30%, or 40%, or 50% or alternativelyat least 55% or alternatively at least 60% of visible light on at leastone side of the netting. In one embodiment of a reflective netting, thenetting may reflect at least 40% solar radiation on average across theUV (wavelength about 280-400 nm), visible (wavelength about 400-700 nm)and very near infrared (wavelength about 700-800 nm) ranges, and whichtransmits at least 10% or 5% on average of solar radiation across thewavelength range about 800-2500 nm. The netting may reflect more solarradiation than it transmits and absorbs in the UV, visible, and verynear infrared ranges. The material may transmit at least 15% or at least20% of solar radiation on average in the wavelength range about 800-2500nm. Some or all yarn of a reflective netting may be formed from a resincomprising a white pigment, which resin has been formed by mixing amasterbatch consisting essentially of 20 to 90% by weight of a whitepigment or combination of pigments chosen from zirconium, strontium,barium, magnesium, zinc and calcium pigments, and a first polymer, witha second polymer such that the resin (masterbatch) comprising the whitepigment comprises between about 5 to 50% by weight of the total mixture.In certain embodiments the white pigment may be selected from zirconium,dioxide, magnesium, zirconate, calcium zirconate, strontium zirconate,barium zirconate, zirconium silicate, zinc sulphide, calcium carbonate,barium sulphate, magnesium oxide, strontium carbonate, barium carbonate,potassium titanate and titanium dioxide.

The term “cover factor” means the percentage of the overall area of thenetting material which comprises knitted, woven, or non-wovenmonofilament, yarn, or tape or a combination, forming the nettingitself, judged from perpendicular to the plane of the netting when laidout flat, as opposed to air space in between the netting. Thus if anetting has a cover factor of 20% then the air space through the nettingwould be 80% of the total area of the netting.

The term “comprising” as used in this specification and claims means“consisting at least in part of”. When interpreting each statement inthis specification and claims that includes the term “comprising”,features other than that or those prefaced by the term may also bepresent. Related terms such as “comprise” and “comprises” are to beinterpreted in the same manner.

As used herein the term “and/or” means “and” or “or”, or both.

As used herein “(s)” following a noun means the plural and/or singularforms of the noun.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will be described by way ofexample only and with reference to the drawings, in which:

FIG. 1 is a schematic diagram of crop protection netting fully coveringan entire row of plants in accordance with an embodiment of theinvention;

FIG. 2 is a schematic diagram of crop protection netting partiallycovering a plant in the form of a canopy in accordance with anembodiment of the invention;

FIG. 3 is a plan view of a portion of the crop protection netting in ataut but un-stretched state in accordance with an embodiment of theinvention;

FIG. 4 is a plan view of a portion of the crop protection netting ofFIG. 3 that has been stretched outwardly in the direction of arrows L;

FIG. 4a is a plan view of a portion of the crop protection netting ofFIG. 3 that has been stretched outwardly in the direction of arrows Lthe opposite of FIG. 4;

FIG. 5 is a closer view of a smaller portion of the crop protectionnetting than shown in FIG. 6a-6d , and in which three separatemonofilament yarns or strands of the netting are shown each in adifferent shade;

FIG. 5.1 is a closer view of a small portion of a variation of the cropprotection netting with extra looping than shown in FIGS. 6a-6d , and inwhich three separate monofilament yarns or strands of the netting areshown each in a different shade;

FIGS. 6a-c each show the path of one of the three yarns in an individualintersection in the netting, and FIG. 6d shows enlarged an individualintersection, again with each yarn or strand shown in a different shadeas in FIG. 5;

FIGS. 6.1a-c each show the path of a one of the three yarns in anindividual intersection in the variation of the crop protection nettingwith extra looping, and FIG. 6.1d shows enlarged an individualintersection, again with each yarn or strand shown in a different shadeas in FIG. 5.1;

FIG. 7 is another plan view of a portion of the crop protection nettingof FIGS. 3-6 d;

FIG. 7.1 is another plan view of a portion of the variation of the cropprotection netting of FIGS. 5.1 and 6.1;

FIG. 8 is a plan view of one prior art netting;

FIG. 9 is a plan view of another prior art netting; and

FIG. 10 is a plot of the results of comparative trials work comparingthe performance of netting of FIGS. 3 to 6 d to a standard pillar typeconstruction insect deterrent netting of the type shown in FIG. 8, inthe prevention of pollination during flowering and thus the productionof seedless fruit.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The crop protection netting of the invention is particularly suitablefor covering trees or other plants for insect and bird exclusion.Particularly, the crop protection netting may be used over fruit treesincluding citrus trees to exclude insects that cause pollination in turnproducing fruit with seeds. The netting is also stretchable orelongatable in both axes or directions, in the plane of the netting whenlaid flat, so that as trees or plants covered by the netting grow thenetting can stretch to accommodate growth. The netting also does notcomprise a relatively high level of knotting in the nettingconstruction, which can add weight to the netting which weight mayundesirably bear on often delicate foliage of covered plants. Inparticular the netting does not comprise lines of knotting formed byknotting the yarn upon itself along these lines, and also the nettingyarn on all sides of the netting mesh apertures is not continuouslyknitted or knotted

FIG. 8 shows one type of prior art crop protecting netting of a lineknit construction. The netting comprises parallel lines or ribs 50formed by knotting the yarn upon itself along these lines, which arejoined by cross-portions 51 of the yarn. The ribs 50 essentiallycomprise rows of tight knots. In the knots of the lines 50 theindividual yarns are tied to one another and cannot move (or can moveonly marginally under strong tension). Yarn is knotted at one line 50and then looped via a cross-portion 51 to the next line 50 then this isrepeated down the rib line(s) so that there are two yarns knotted thenthe next two looped (as part of one loop) and so on. As a result theyarn is non-stretch or elongatable at least in the axis along the ribs.Also the high level of knotting in the lines or ribs 50 makes thenetting relatively heavy.

FIG. 9 shows another form of prior art crop protecting nettingcomprising diamond shaped apertures with the netting lines 60 beingknitted or knotted as shown. This netting is also relatively heavy dueto the continuous knotting in all directions/along all sides of thediamond shaped apertures. Also the knit construction comprisingcontinuous knotting in all directions/along the netting sides of thediamond shaped apertures inhibits knitting this form of netting with asmall aperture size such as a 4 mm aperture size or example and itrestricts the weaving of lighter weight netting.

Referring to FIG. 1, a length of crop protection netting 10 of theinvention is shown placed over a row of fruit trees 12. The netting maybe manufactured in a length and width to suit typical applications or arange of lengths and/or widths. Typically the width of the netting isbetween about 2 and 20 meters and the length of the netting is longer.For insect exclusion typically the netting must be large enough toextend over an entire plant or row of plants as shown, and be secured,fastened or anchored at or toward the peripheral edges 11 of the nettingwith stakes, pegs, soil or other fixing devices to the ground 15surrounding the periphery of the plant or plants such that bees or otherinsects cannot fly under the netting into the trees. Alternatively, theedges 11 of the netting may drape onto the ground and need notnecessarily be secured in any way other than under its own weight. Asshown in FIG. 1, the netting 10 is draped over the trees such that it isin contact with and supported in place by the trees it covers.

FIG. 2 shows an alternative installation of crop protection netting ofthe invention as a canopy extending over the top of a fruit tree 12, andthis installation may be applied over/along a row of trees also. Thecanopy installation comprises a supporting structure 13 or frameworkthat supports or suspends the netting 10 over the fruit trees. Thenetting may also be arranged such that its peripheral edges 11 extend atleast some way toward the ground 15 if more or full coverage is desired.The supporting structure 13 may comprise one or more upright posts aloneor in combination with supporting wire or wires or other cross-membersextending between the posts.

FIG. 3 is a plan view of a portion of crop protection netting of apreferred embodiment of the invention in a taut but un-stretched stateand FIG. 4 is a plan view of a portion of the netting stretchedoutwardly in the direction of arrows L. Optionally edge portions (notshown) of the netting may be reinforced or formed with differentmaterial to assist in fixing the netting to the ground. As shown, theentire netting or majority of the netting if the edges are reinforced isformed from a knitted mesh construction shown.

The netting is typically machine-knitted on a warp knitting machine orother knitting-machine. The netting comprises an array of mesh apertures14. The mesh apertures 14 of the preferred embodiment are shaped as seenin FIG. 7, a combination of rounded base and pointed peak, forming foursides with four yarn intersections points and are substantially uniformin shape and size. The orientation of the mesh apertures 14 relative tothe length L and width W directions of the netting need not be as shownin FIG. 3.

Referring particularly to FIG. 3 each shaped mesh aperture 14 is definedsubstantially by four sides 14 a-14 d of substantially equal length ofyarn, which are connected by four knit intersections 14 e. At the knitintersections 14 e the yarns of which the netting is formed are loopedaround each other. Between the yarn intersections 14 e the connectingyarn portions 14 a-14 d extend substantially linearly and are notcontinuously knitted or knotted (as in the prior art netting typesreferred to above). The sides 14 a-d may have non-equal lengths inalternative forms of the netting. As shown, the sides 14 a-14 d betweenthe intersections 14 e comprise twin yarns, but be comprised of tripleor multiple yarns in alternative embodiments. In the four-sided form ofthe mesh apertures, the shape of the apertures may be substantiallysquare, rectangular or any other shape. It will also be appreciated thatthe mesh apertures may be knitted to have more than four sides, and withintersections 14 e in alternative forms of the knitted mesh constructionto create more complex mesh aperture shapes, for example but not limitedto hexagonal shaped apertures.

The netting is stretchable or extendible in both the width axis ordirection indicated by arrow W and the length axis or directionindicated by arrow L in FIGS. 3 and 4 which is typically the machine ormanufacturing direction. FIG. 4 shows a portion of the crop protectionnetting of FIG. 3 that has been stretched in the length direction L(causing some contraction or reduction in the width direction W and alsocausing the mesh apertures 14 to change shape). FIG. 4a shows a portionof the crop protection netting of FIG. 3 that has been stretched in thewidth direction W (causing some contraction or reduction in the lengthdirection L and also causing the mesh apertures 14 to change shape.

In the preferred embodiment shown the mesh size of the equi-length foursided mesh apertures 14 is defined by the length of the sides 14 a-dbetween the intersections 14 e, measured when the netting is in a tautbut non-stretched state in both length and width directions. Preferablythe mesh size may be in the range of approximately 3 mm to 20 mm, 3 mmto 10 mm, more preferably approximately 3 mm to 8 mm, even morepreferably 4 mm to 6 mm, even more preferably 3 mm to 5 mm, even morepreferably approximately 3.5 mm to 4.5 mm. In one preferred form forpollinating insect exclusion the mesh size may be approximately 4 mm.

The yarn from which the netting is knitted is typically a monofilamentyarn of any suitable material as previously mentioned. Typically, theyarn is extruded from a polymer resin. Each yarn yarns may be singlemonofilaments, or alternatively may comprise twin or multiplemonofilaments. The monofilament yarns may be circular in cross-sectionor otherwise shaped. For circular monofilament yarns, the yarnpreferably has a diameter in the range of approximately 0.1 mm to 1 mm,even more preferably 0.2 mm to 0.8 mm, and even more preferably 0.2 mmto 0.4 mm, and more preferably 0.15 to 0.3 mm and most preferably 0.15mm to 0.25 mm. In denier (grams per 9000 meters of the yarn) the yarn ispreferably in the range of approximately 50 to 1000 denier, morepreferably 50 to 700 denier, even more preferably 100 to 500 denier,even more preferably 100 to 300 denier, even more preferably 150 to 250denier or most preferably 200 to 300denier. The monofilament yarn may bestretchable or non-stretchable in length, and may be elastic ornon-elastic depending on requirements. The netting is relativelylightweight. The weight of the netting is preferably in the range ofapproximately 10 to 100 grams per m², more preferably 15 to 80 grams perm², even more preferably 20 to 60 grams per m², even more preferably 20to 40 grams per m², even more preferably 30 to 40 grams per m²and evenmore preferably 25 to 35 grams per m² and most more preferably 30 to 40grams per m²

The crop protection netting may have a cover factor (as herein defined)of less than 30%, less than 20%, less than 10%, or less than 5%.

Referring now particularly to FIG. 5 which is a closer view of a smallportion of the netting with three separate monofilament yarns or strandsof the netting shown each in a different shade, and FIGS. 6a-c whicheach show the path of a one of the three yarns in an individualintersection in the netting and FIG. 6d which shows enlarged anindividual intersection circled by a dashed line again with each yarn orstrand shown in a different shade, each intersection is formed byknitting together of three yarn parts (of three yarns extendinglengthwise beside each other) passing through the intersection:

-   -   a first yarn 22 which enters the intersection along a first axis        A and exits the intersection along the same first axis, so that        a first connecting portion 22 a to a first adjacent intersection        (of the four connecting portions to the intersection from four        immediately adjacent and surrounding intersections) comprises        adjacent lengths of the same yarn 22    -   a second yarn 20 which enters the intersection along a second        axis B, passes through (and around) the loop within the        intersection of the first yarn 22, and extends to and returns        from a second adjacent intersection along a third axis C so that        a second connecting portion 20 a to that adjacent intersection        comprises adjacent lengths of the same yarn 20, and exits the        intersection along a fourth axis D, and    -   a third yarn 21 which enters the intersection along second axis        B so that a third connecting portion 21 a from a third adjacent        intersection comprises portions of both yarns 20 and 21, passes        through the loop in the intersection of the first yarn 22, and        exits the intersection along fourth axis D with yarn 20, so that        a fourth connecting portion 24 a to a fourth adjacent        intersection comprises portions of both yarns 20 and 21.

Referring now particularly to FIG. 5.1 that is showing a variation onthe knit pattern of FIG. 5, this variation has extra looping, which is acloser view of a small portion of the netting with three separatemonofilament yarns or strands of the netting shown each in a differentshade, and FIGS. 6.1a-c which each show the path of a one of the threeyarns in an individual intersection in the netting and FIG. 6.1d whichshows enlarged an individual intersection circled by a dashed line againwith each yarn or strand shown in a different shade, each intersectionis formed by knitting together of three yarn parts (of three yarnsextending lengthwise beside each other) passing through theintersection:

-   -   a first yarn 122 which enters the intersection and does an extra        loop before entering axis 1A, then extends along a first axis 1A        and exits the intersection along the same first axis, so that a        first connecting portion 122 a to a first adjacent intersection        (of the four connecting portions to the intersection from four        immediately adjacent and surrounding intersections) comprises        adjacent lengths of the same yarn 122    -   a second yarn 120 which enters the intersection along a second        axis 1B, passes through (and around) the loop within the        intersection of the first yarn 122, and then goes behind the        loop created by the first yarn 122 to create an extra loop then        extends to and returns from a second adjacent intersection along        a third axis 1C so that a second connecting portion 120 a to        that adjacent intersection comprises adjacent lengths of the        same yarn 120, and exits the intersection along a fourth axis        1D, and    -   a third yarn 121 which enters the intersection along second axis        1B so that a third connecting portion 121 a from a third        adjacent intersection comprises portions of both yarns 120 and        121, passes through the loop in the intersection of the first        yarn 122, and exits the intersection along fourth axis 1D with        yarn 120, so that a fourth connecting portion 124 a to a fourth        adjacent intersection comprises portions of both yarns 120 and        121.

The extra looping in FIGS. 5.1 and 6.1 creates a similar net to FIGS. 5and 6 but the extra looping gives a reduction in how stretchable the netis and this may in some applications be a more desired option. A planview of FIGS. 5.1 and 6.1 is shown in FIG. 7.1.

Another feature of the netting construction of the preferred embodimentis that each yarn intersection in the netting is connected to adjacentand surrounding yarn intersections by the connecting yarn portions 14a-d each comprising at least two yarn lengths. In a preferredembodiment, each yarn intersection in the netting is connected toadjacent and surrounding yarn intersections by connecting yarn portionseach comprising at least two yarn lengths that are at least free ofknots or loops for 2 mm or more in length between the intersections.

This intersection knitting is repeated at each intersection in thenetting. FIG. 5 shows the path of individual yarns in a larger portionof the netting. FIG. 7 shows a section of the material in which someindividual yarns are shown in a contrasting colour from which it can beseen how individual yarns proceed down the length L of the material inthe warp direction. Arrow L in FIG. 7 also indicates the machine ormanufacturing direction. The many individual yarns all extend along thelength of the netting and each yarn follows an approximate lengthwisezig-zag path path, looping at each intersection in the nettingcomprising the yarn to one side and then to another side so that islinked to the two adjacent pairs of yarns on both sides. Referring toFIG. 7 it can be seen that there is a pattern of zig-zags of two yarnparts, such as indicated at 30, between intersections 14 e, with a loop,such as indicated at 31, to one side and then a loop, such as indicatedat 32, to the other side, from successive intersections.

Netting of the invention may be formed from synthetic yarn of a polymercontaining pigments which give the material desired properties, such asdesired light reflective, absorptive and/or transmission properties forexample. In some embodiments, the yarn may be reflective as previouslydescribed, for example by using yarns having a white pigment. Thisreflection may provide various benefits to the trees or plants beingcovered, but may also enhance the visibility of the netting to insectssuch as pollination insects thereby increasing the deterrence effect ofthe netting to insects. For example crop protection netting of theinvention may be knitted from yarn which reflects at least 10% or atleast 50% of solar radiation on average across the UV (wavelength about280-400 nm), visible (wavelength about 400-700 nm) and very nearinfrared (wavelength about 700-800 nm) ranges, and which transmits atleast 10% on average of solar radiation across the wavelength rangeabout 800-2500 nm. In some embodiments the yarn may reflect more solarradiation than it transmits and absorbs in the LTV, visible, and verynear infrared ranges. In some embodiments the yarn may transmit at least15% or at least 20% of solar radiation on average in the wavelengthrange about 800-2500 nm. In some embodiments the yarn may reflect atleast 10% on average of solar radiation across the wavelength rangeabout 800-2500 nm. In some embodiments the yarn may be knitted from yarnfrom a resin comprising at least 4% or at least 8% or at least 10% or atleast 12% or at least 14% or at least 16% or at least 18% or at least20% or at least 25% by weight of at least one white pigment. In someembodiments white pigment comprises a zirconium, strontium, barium,magnesium, zinc, calcium, titanium, or potassium pigment or acombination thereof, such as zirconium dioxide, magnesium zirconate,calcium zirconate, strontium zirconate, barium zirconate, zirconiumsilicate, zinc sulphide, calcium carbonate, barium sulphate, magnesiumoxide, strontium carbonate, barium carbonate, titanium dioxide,potassium oxide, potassium titanate or a combination thereof. The whitepigment may be present in the form of particles of size 0.02-5 micronsor 0.1-3 microns.

As stated the crop protection netting of the invention is particularlysuitable covering trees or other plants for insect and bird exclusion.Particularly, the crop protection netting may be used over fruit treesincluding citrus trees to exclude insects that cause pollination in turnproducing fruit with seeds. The netting is also stretchable so that astrees or plants covered by the netting grow the netting can stretch toaccommodate growth. The netting also does not comprise a relatively highlevel of knotting in the netting construction, which can add weight tothe netting which weight may undesirably bear on often delicate foliageof covered plants.

Trials

The following description of trials work further illustrates theinvention and in particular performance of netting of the preferredembodiment of the invention described above and illustrated in producinga higher proportion of seedless fruit than prior art insect deterrentnetting. Clementine mandarins produce seedless fruit only if flowers arenot pollinated prior to fruit set. The main mechanism of pollination forthis variety is via bees. A study was undertaken in a mature Clementinemandarin block to assess the effectiveness of insect deterrent nettingof the invention relative to a standard pillar type construction insectbee deterrent netting of the type shown in FIG. 8, in the prevention ofpollination during flowering. Two adjacent rows of Clementine mandarintrees during the flowering period were covered one with a white colouredUV reflecting monofilament netting of the invention as described hereinand illustrated in FIGS. 3 to 6 of mesh aperture size 4 mm and 200denier (a mesh aperture size of 4×4 mm across the axes of the generallydiagonal netting apertures) and the other with clear pillar netting asshown in FIG. 8 with 3×7 mm apertures. Both nettings were placed beforethe first flower was open and removed around 6 weeks later when the lastflower had opened and set. At harvest 200 fruit from each row wereassessed for the presence and number of fully formed seeds. Statisticalanalysis was carried out using general liners models analysis (NCSSsoftware). The results are shown in FIG. 10. The trees covered with thenetting of the invention produced significantly less fruit with one ormore seeds than the trees covered with the standard pillar net—namely 3%vs 12%, α=0.05.'

The foregoing description of the invention includes preferred formsthereof. Modifications may be made thereto without departing from thescope of the invention as defined in the accompanying claims.

The invention claimed is:
 1. Crop protection netting comprising agreater length than width and which is of a knitted mesh construction,said knitted mesh construction knitted such that at yarn intersectionsin the netting multiple yarns of which the netting is formed are knittedaround each other to define the netting mesh apertures and so that thenetting is stretchable in length and width directions, said knitted meshconstruction comprising connecting yarn portions between said yarnintersections, said connecting yarn portions extending substantiallylinearly between intersections, and each yarn intersection in thenetting being connected to adjacent and surrounding yarn intersectionsby said connecting yarn portions, each of said connecting yarn portionscomprising at least two yarn lengths that are free of knots or loops forat least 2 mm or more in length between the intersections and whereinthe netting has a mesh size in the range 3 mm to 6 mm, the multipleyarns have a diameter up to 0.4 mm, and the netting has a weight up to80 grams per m².
 2. Crop protection netting according to claim 1 whereinthe yarn intersections in immediately adjacent rows are staggeredrelative to each other.
 3. Crop protection netting according to claim 1wherein the netting is knitted from multiple yarns all extending along alength of the netting.
 4. Crop protection netting according to claim 1wherein in the netting each yarn follows an approximate zig-zag pathalong the length of the netting, looping at each intersection in thenetting comprising the yarn, to a further netting yarn intersection oneon one side and one on another side.
 5. Crop protection nettingaccording to claim 1 wherein each intersection is formed by knittingtogether of three yarn parts passing through the intersection: a firstyarn which enters the intersection along a first axis and exits theintersection along the same first axis, so that a first connectingportion to a first adjacent intersection comprises adjacent lengths ofthe same yarn, a second yarn which enters the intersection along asecond axis, passes through the loop within the intersection of thefirst yarn, and extends to and returns from a second adjacentintersection along a third axis so that a second connecting portion tothat adjacent intersection comprises adjacent lengths of the same yarn,and exits the intersection along a fourth axis, and a third yarn whichenters the intersection along the second axis so that a third connectingportion from a third adjacent intersection comprises portions of boththe second and third yarns, passes through the loop in the intersectionof the first yarn, and exits the intersection along fourth axis with thesecond yarn, so that a fourth connecting portion to a fourth adjacentintersection comprises portions of both the second and third yarns. 6.Crop protection netting according to claim 1 wherein each intersectionis formed by knitting together of three yarn parts passing through theintersection: a first yarn which enters the intersection along a firstaxis, firstly creates an extra loop and exits the intersection along thesame first axis, so that a first connecting portion to a first adjacentintersection comprises adjacent lengths of the same yarn, a second yarnwhich enters the intersection along a second axis, passes through theloop within the intersection of the first yarn, and then goes behind theloop created by the first yarn to create an extra loop and then extendsto and returns from a second adjacent intersection along a third axis sothat a second connecting portion to that adjacent intersection comprisesadjacent lengths of the same yarn, and exits the intersection along afourth axis, and a third yarn which enters the intersection along thesecond axis so that a third connecting portion from a third adjacentintersection comprises portions of both the second and third yarns,passes through the loop in the intersection of the first yarn, and exitsthe intersection along fourth axis with the second yarn, so that afourth connecting portion to a fourth adjacent intersection comprisesportions of both the second and third yarns.
 7. Crop protection nettingaccording to claim 1 wherein each mesh aperture is defined substantiallyby the knitted yarn on four sides between four looped or knotted knitintersections.
 8. Crop protection netting according to claim 1 formedfrom elastic yarn.
 9. Crop protection netting according to claim 1formed from monofilament yarn.
 10. Crop protection netting according toclaim 1 formed from twin or multiple filament yarn.
 11. Crop protectionnetting according to claim 1 wherein the yarn has a weight in the rangeof approximately 50 to 1000 denier.
 12. Crop protection nettingaccording to claim 1 which has been produced on a warp knitting machine.13. Crop protection netting according to claim 1 which is white incolour.
 14. A crop protection netting according to claim 1 which isknitted from yarn which reflects at least 30% solar radiation on averageacross the UV (wavelength about 280-400 nm).
 15. Crop protection nettingaccording to claim 1 comprising a cover factor of less than 30%. 16.Crop protection netting according to claim 1 which is knitted from yarnfrom a resin comprising at least 4% by weight of at least one whitepigment.
 17. Crop protection netting according to claim 1 wherein thenetting is knitted from multiple yarns all extending along a length ofthe netting.
 18. Crop protection netting according to claim 1 whereinthe multiple yarns from which the netting is formed comprise acombination of monofilament or twin or multiple filament yarn, and tape.19. Crop protection netting according to claim 1 which has a weight upto 60 grams per m².
 20. Crop protection netting according to claim 1which is transparent or translucent.
 21. A method which includessupporting over one or more plant(s) as a canopy protection nettingaccording to claim
 1. 22. Crop protection netting comprising a knittedmesh construction which is stretchable in multiple directions, saidknitted mesh construction comprising connecting yarn portions betweenknitted yarn intersections which extend substantially linearly betweenthe yarn intersections, and are free of knots or loops between theintersections said knitted mesh construction being knitted from multipleyarn, and wherein said connecting yarn portions between said knittedyarn intersections each comprise at least two yarn lengths, and whereinthe netting has a mesh size in the range of approximately 2 mm to 10 mm,the multiple yarns have a diameter in the range of approximately 0.1 mmto 1 mm, and the netting has a weight in the range approximately 10 to100 grams per m².